大吸水率粗集料高性能海工混凝土配合比设计研究

摘要

以马普托大桥工程为背景,使用吸水率达3.0%以上的粗集料Namaacha碎石(N石)和Hipermaquinas碎石(H石)研究高性能海工混凝土的配合比设计.结果表明,N石的吸水速率以及饱和吸水量均大于H石,主要原因在于N石所含孔体积大于H石,且孔径比H石更大.根据2种碎石的性能,选择N石进行C40海工混凝土配合比设计,确定最佳水胶比为0.38,粉煤灰掺量为35%;选择H石进行C50海工混凝土配合比设计,确定最佳水胶比为0.33,粉煤灰掺量为20%.最佳配合比的C40、C50混凝土海水浸泡180 d的抗压强度与标养条件下接近,RCM法测试的365 d氯离子迁移系数小于1.6×10-12m2/s,具有抗海水侵蚀性能.%Based on Maputo bridge project,mix design of high performance marine concrete is studied using coarse aggregate Namaacha gravel(N)and Hipermaquinas gravel(H)with high water absorption above 3.0%. The results show that the water absorp-tion rate and saturated water absorption of N are larger than that of H. The main reason is that the pore volume of N is larger than that of H stone,and the pore diameter is larger than that of H stone. According to the performance of the two kinds of grav-el,the mix design of C40 marine concrete using N gravel is water-cement ratio of 0.38 and the fly ash content of 35% and the mix design of C50 marine concrete using H gravel is water-cement ratio of 0.33 and the fly ash content of 20%. Seawater immer-sion experiment on the optimum mixing ratio of C40,C50 concrete shows that the 180 d compressive strength test results and stan-dard conditions strength test results are similar,chloride Ion diffusion coefficients of concrete in 365 d are less than 1.6×10-12m2/s by RCM method. The results show that the design of marine concrete has resistance to seawater erosion.